Virus Definition, History, Parts, Characteristics, and Shape – Humans are susceptible to disease. The causes can vary, one of which is often found is viruses, which are microbes that are parasitic in microscopic size and tend to work by infecting the host.
Viruses can act as disease agents and inherited agents of nature. As an agent of the disease, the virus enters the cell and causes harmful changes to the cell, which can eventually damage or even cause death in the cells it infects.
As an inherited agent of the trait, the virus enters the cell and stays inside the cell permanently.
The resulting changes are not harmful to cells or even beneficial. In some cases, the virus can act as a disease agent or as an inherited agent of properties depending on its host cells and environmental conditions.
Cells in the human body, related to its development and function, it can be disrupted by the infection due to microorganisms called viruses. The type of infected cells and the type of virus that infects will cause different diseases and symptoms as well.
The virus is another word for poison. Viruses are microscopic parasites that infect cells of biological organisms.
Viruses can only reproduce in living materials by utilizing living cells. Because the virus does not have cellular equipment to reproduce itself.
History of viruses
The history of the discovery of the virus occurred in 1883. German scientist Adolf Mayer is looking into the causes of mosaic disease in tobacco.
A mosaic, the disease that inhibits the growth of tobacco plants and cause their leaves to speckle.
Adolf Mayer discovered the disease was contagious when transferring from diseased plants to other plants by spraying sap.
Mayer, then searched for microbes in the sap that transmit the disease but got nothing. He concluded that the disease was caused by small bacteria that could not be seen under a microscope.
In 1892, Russian scientist Dimitri Ivanowsky tested Adolf Mayer’s hypothesis by draining sap from infected tobacco leaves through a sieve designed to pick up bacteria.
When filtered, the sap still causes mosaic disease. He still holds on to the hypothesis that bacteria cause mosaic disease.
In 1897, Dutch botanist Martinus Beijerinck discovered that filtered sap could reproduce.
In 1935, American scientist Wendell Stanley successfully crystallized particles of mosaic disease known as the tobacco mosaic virus (TMV). Then TMV and many other types of viruses can be seen with the help of electron microscopes.
The body of the virus in the form of crystals or particles is more characteristic of minerals than the characteristics of life. Therefore, there is a presumption that viruses are not living things. Structurally the virus consists of 3 parts, namely:
- The capsid is a layer of the virus body wrapping in the form of protein.
- The head of the virus contains genetic material (nucleic acid), namely DNA or RNA.
- The tail is an important part of the body of the virus to attach itself to the cell as well as to insert the genetic material of the virus into the host cell.
The characteristics of the virus are as follows.
- Viruses can be like living things, for example, it can multiply if they are in living cells.
- It has one nucleic acid, DNA or RNA alone.
- Viruses can be like inanimate objects, for example not metabolic, not breathing, not moving, and crystal-shaped if they are outside living cells.
- Very small in size, which is between 20 and 300 nm.
As it turns out, viruses vary in shape. Want to know anything?
- Rod-shaped, e.g. TMV (Tobacco Mosaic Virus).
- It is rod-shaped and oval-tipped like a bullet, for example Rhabdovirus.
- Round shape, e.g. HIV (Human Immunodeficiency Virus) and Orthomyxovirus.
- It is in the form of filaments or threads, e.g. The Ebola virus.
- It is polyhedral, for example Adenovirus.
- Shaped like the letter T, for example, bacteriophage, which is a virus that attacks the Escherichia coli bacteria.
Thank you very much for reading Virus Definition, History, Parts, Characteristics, and Shape, hopefully useful.